8.1 Structured Documentation

Most of the small changes to the LATEX markup have been made
with an eye to divorcing the markup from the presentation, making
both a bit more maintainable. Over the course of 1998, a large
number of changes were made with exactly this in mind; previously,
changes had been made but in a less systematic manner and with
more concern for not needing to update the existing content. The
result has been a highly structured and semantically loaded markup
language implemented in LATEX. With almost no basic TEX or
LATEX markup in use, however, the markup syntax is about the
only evidence of LATEX in the actual document sources.

One side effect of this is that while we've been able to use
standard ``engines'' for manipulating the documents, such as
LATEX and LATEX2HTML, most of the actual transformations have
been created specifically for Python. The LATEX document
classes and LATEX2HTML support are both complete implementations
of the specific markup designed for these documents.

Combining highly customized markup with the somewhat esoteric
systems used to process the documents leads us to ask some
questions: Can we do this more easily? and, Can we do this
better? After a great deal of discussion with the community, we
have determined that actively pursuing modern structured
documentation systems is worth some investment of time.

There appear to be two real contenders in this arena: the Standard
General Markup Language (SGML), and the Extensible Markup Language
(XML). Both of these standards have advantages and disadvantages,
and many advantages are shared.

SGML offers advantages which may appeal most to authors,
especially those using ordinary text editors. There are also
additional abilities to define content models. A number of
high-quality tools with demonstrated maturity is available, but
most are not free; for those which are, portability issues remain
a problem.

The advantages of XML include the availability of a large number
of evolving tools. Unfortunately, many of the associated
standards are still evolving, and the tools will have to follow
along. This means that developing a robust tool set that uses
more than the basic XML 1.0 recommendation is not possible in the
short term. The promised availability of a wide variety of
high-quality tools which support some of the most important
related standards is not immediate. Many tools are likely to be
free.